On 02/22/2017 01:06 PM, Ard Biesheuvel wrote:
If we simply put an MBR in sector 0 that does not cover sector 1 at all (or any subsequent sectors that are part of the primary boot image), I don't think we need to bother at all with GPTs or protective MBRs or anything else that is specific to UEFI. Let's just start the first partition at the next eraseblock boundary, and make it around 128 MB in size, so we can use it as the EFI System Partition (ESP).
Is there any reason, other than the read-modify-write cost of writes smaller than the erase block size that you suggest the first partition lies at the next erase block boundary?
The MBR at offset 0 and the boot loader at offset 1 LBA will (most likely) have to be in the same erase block. I do realize that we don't want to be rewriting these blocks with writes to the front of the first partition.
I just want to be sure I'm not missing some other constraint. Thanks.
-Alex